Thin-film magnetic head with variable-volume cavity in medium-opposed surface

Abstract

Provided is a thin-film magnetic head in which the magnetic spacing can be appropriately controlled by dynamically and accordingly, by adjusting the pressure working between the thin-film magnetic head and the magnetic recording medium according to the change of conditions such as the change over time. The thin-film magnetic head comprises at least one cavity for adjusting a pressure working between the thin-film magnetic head and the magnetic recording medium, provided in a surface of the head opposed to the magnetic recording medium, and a volume of the at least one cavity being variable. When the magnetic recording medium passes through near the cavity, the cavity generates a (negative) pressure that attracts the head and the medium toward each other. The amount of the negative pressure depends on the volume of the cavity; thus, a magnetic spacing dMS can be controlled dynamically and accordingly by adjusting the volume.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a thin-film magnetic head used for magnetic recording, especially to a tape head for reading data from a magnetic tape and / or writing data to a magnetic tape. The present invention further relates to a magnetic tape apparatus provided with the tape head. The present invention furthermore relates to a method for controlling a magnetic spacing that is a distance between the end of the head element in the thin-film magnetic head and the surface of the magnetic record layer of the magnetic recording medium.[0003]2. Description of the Related Art[0004]In recent years, magnetic recording and reproducing apparatuses have been remarkably improved in capacity of storage data, corresponding to the widespread use of multimedia and the Internet. And magnetic tape apparatuses for backing up or storing data or for recording and reproducing audio video information are no exception of this trend of larg...

AI Technical Summary

Benefits of technology

[0013]Therefore, an object of the present invention is to provide a thin-film magnetic head in which the magnetic spacing can be appropriately controlled, by dynamically and accordingly adjusting the pressure working between the thin-film magnetic head and the magnetic recording medium according to the change of conditions such as the change over time, and to provide a magnetic tape apparatus provided with the just-described thin-film magnetic head.

[0020]In the thin-film magnetic head provided with the closure, the thin-film magnetic head preferably further comprises at least one volume-adjusting means for adjusting the volume of the at least one cavity. In the case, at least one volume-adjusting means is also preferably at least one heating element. The heat generated from the heating element causes a portion near the cavity to be thermally expanded; then, the inner wall of the cavity moves inward. Thus, controlling the amount of heat generated from the heating element enables the volume of the cavity to be adjusted.

[0021]Further in the case that the volume-adjusting means is the heating element, preferably further provided is at least one thermal expansion portion formed of a material with a coefficient of linear expansion larger than coefficients of linear expansion of the overcoat layer and the closure, positioned adjacent to the at least one cavity. By providing the thermal expansion portion, a desired change in volume of the cavity can be obtained with use of the less amount of heat generated from the heating element. Further, the less amount of heat facilitates suppressing the change in shape of the sliding surface due to the heat generated from the heating element. As a result, improved is the flexibility in the design of the setting place of the heating element in relation to the sliding surface.

[0035]According to the present invention, a controlling method of a magnetic spacing is further provided, which comprises the step of adjusting a pressure working between a thin-film magnetic head and a magnetic recording medium by adjusting a volume of at least one cavity provided in a surface of the thin-film magnetic head, the surface being opposed to the magnetic recording medium. In the controlling method, by adjusting the volume of the at least one cavity, the pressure working between the thin-film magnetic head and the magnetic recording medium can be adjusted dynamically and accordingly, according to the change of conditions such as the change over time. As a result, the magnetic spacing can be controlled appropriately.

Problems solved by technology

However, there has been a problem that the magnetic spacing is likely to vary due to the change in pressure working between the thin-film magnetic head and the magnetic recording medium.

Further, in some cases, the head performance may be degraded due to frictional heat generated by the contact.

Furthermore, in some cases, the magnetic spacing may become larger due to the change in shape of the TBS or due to the burning and depositing of the wear debris described above, which would cause the read output to be decreased, or cause the peak steepness of the read signal to be degraded.

Therefore, the tape head cannot control the magnetic spacing in response to the changing conditions.

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